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(11) | EP 2 943 141 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
DENTAL DRILL BIT AND SURGICAL TEMPLATE ZAHNÄRZTLICHER BOHRER UND CHIRURGISCHE SCHABLONE FORET DENTAIRE ET GABARIT CHIRURGICAL |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a dental drill bit. The present invention also relates to the use of such a dental drill bit. The present invention also relates to a method of drilling a hole in an oblique bone surface of a jaw bone of a patient.
[0002] A known drill bit for drilling a hole in the jaw bone of a patient comprises a cutting point at the tip of a cylindrical shaft with helical flutes. The cutting point has two straight cutting edges defining a point angle. Such a drill can be used in guided dental surgery ('Guided Twist Drill'). However, such a drill bit is not that suitable for drilling a hole in an object or surface which is very oblique in relation to the longitudinal axis of the drill bit.
[0003] Another example of a known dental drill bit is the 'Guide Drill' provided by Nobel Biocare. The 'Guide Drill' comprises a spherical drill head. The Guide Drill may be used for freehand surgery. US 2010/112517 A1 discloses a dental drill bit having a spherical drill head. The present invention is defined in the appended independent claims. Embodiments are defined in the appended dependent claims.
[0004] According to an aspect of the present invention, there is provided a dental drill bit in combination with a surgical template provided with a guide hole adapted to guide the dental drill bit directly or via a guide sleeve provided in the guide hole, the dental drill bit comprising a first end, a second end, a spherical drill head arranged at the first end, and at least one helical flute extending from the spherical drill head towards the second end. The portion of the dental drill bit having the at least one helical flute may be substantially cylindrical, to fit in the guide hole/guide sleeve of the surgical template.
[0007] The dental drill bit may further comprise a longitudinal axis extending through the first end and the second end, wherein the longitudinal axis lies in a plane in which the spherical drill head defines a circle sector having a sector angle equal to or greater than 180 deg.
[0008] A portion of the dental drill bit at the second end may be adapted for attachment to a drilling machine.
[0011] The maximum diameter of the spherical drill tip may be equal or substantially equal to the diameter of the portion of the dental drill bit having the at least one helical flute.
[0012] Another aspect of the present invention relates to the use of the dental drill bit according defined above for guided surgery, especially for drilling a hole in an object or surface which is oblique with respect to the longitudinal axis of the dental drill bit.
[0013] According to yet another aspect of the present invention, there is provided a method of drilling a hole in an oblique bone surface of a jaw bone of a patient, which method comprises: placing a surgical template with a guide hole over the oblique bone surface of the jaw bone, whereby said surface is oblique with respect to the longitudinal axis of the guide hole; inserting a dental drill bit as defined above through the guide hole; and drilling the hole in the oblique surface using the dental drill bit while the dental drill bit is guided by the guide hole or by a guide sleeve provided in the guide hole. This aspect may exhibit the same or similar technical effects and features as the previously defined aspects, and vice versa.
[0014] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing a currently preferred embodiment of the invention.
Fig. 1 is a side view of a dental drill bit according to an embodiment of the present invention.
Fig. 2 is a front view of the dental drill bit of fig. 1.
Fig. 3 is a schematic side view of the drill head of the dental drill bit of fig. 1
Fig. 4 is a perspective view of the drill bit of fig. 1.
Figs. 5a-b are side views showing the drill bit of figs. 1-4 for drilling a hole in an oblique surface using guided surgery.
[0015] Figs. 1-4 show a dental drill bit 10 according to an embodiment of the present invention. The dental drill bit 10 is substantially straight. The dental drill bit 10 comprises a first end 12 and a second, opposite end 14. The dental drill bit 10 further comprises one spherical drill head 16 at the first end 12. The shape (radius) of the spherical drill head 16 can be completely uniform, but alternatively the radius r of the spherical drill head 16 can differ ± 10 %. The spherical drill head 16 comprises a plurality of cutting edges 18. Preferably, the number of cutting edges 18 is in the range of 5-8. Also preferably, the cutting edges 18 are curved. The spherical drill head 16 with the cutting edges 18 is "side cutting", which means that the present drill bit 10 can be used to drill a hole or bore in an oblique surface. Also, the spherical drill head 16 is radially centralized, which means that it is co-axial with the (central) longitudinal axis 20 extending through the first end 12 and the second end 14 of the dental drill bit 10. Also, a seen in a plane in which said longitudinal axis 20 lies, e.g. the plane of fig. 3, the spherical drill head 16 defines a circle sector having a sector angle θ which preferably is equal to or greater than 180°. The sector angle θ may for instance be in the range of about 180° - 220°. The spherical drill head 16 may substantially be of the same type as the spherical drill head of the 'Guide Drill' provided by Nobel Biocare.
[0016] At the second end 14 of the dental drill bit 10, opposite the spherical drill head 16, there is an end portion 22 which is adapted for attachment to a drilling machine (not shown). The end portion 22 may for instance be completely cylindrical, or comprise some other kind of drilling machine interface.
[0017] Between the spherical drill head 16 and the end portion 22, the dental drill bit 10 comprises an intermediate portion 24. In other words, the intermediate portion 24 extends from the spherical drill head 16 to the end portion 22. The intermediate portion 24 may be generally cylindrical throughout its length, with a constant (maximum) diameter D2 as in the illustrated embodiment. The intermediate portion 24 is provided with at least one helical or spiralling flute 26. The at least one helical flute 26 extends from the spherical drill head 16 and towards the second end 14 of the dental drill bit 10, to the end portion 22. The at least one helical flute 26 may allow passage of chips and the admission of cutting fluid (e.g. for cooling). Also, the at least one helical flute 26 can have a relatively low pitch (helix angle) α in the range of 3° - 20° with respect to the longitudinal axis 20. Preferably, the number of helical flutes is two, as in the illustrated embodiment showing a first flute 26a and second flute 26b. The flutes 26a and 26b are "entwined". Namely, they are arranged on opposite sides of the longitudinal axis 20, and they have substantially the same extents along the longitudinal axis 20.
[0018] Preferably, the maximum diameter D1 of the spherical drill tip 16 is equal or substantially equal to the diameter D2 of the intermediate portion 24, in order to create a tight distance between the drilled hole and the intermediate portion 24 to ensure that bone chips are "pumped" through the flute(s) 26 out from the drill hole. The diameters D1 and D2 may for example be in the range of 1.5-6.0 mm. Also, the intermediate portion 24 may be slightly tapered (not shown). In this case, the diameter of the intermediate portion 24 just next to the spherical drill tip 16 equals D1, and then the diameter of the intermediate portion 24 increases towards the end portion 22.
[0019] The present drill bit 10 may be used in various dental applications, such as guided surgery. However, the drill bit 10 could also be used in non-dental application.
[0020] In an exemplary method of drilling a hole 28 in an oblique bone surface 30 of a jaw bone of a patient (see figs. 5a-b), a surgical template 32 with a guide hole 34 is placed over the bone surface 30, whereby said surface is oblique with respect to the longitudinal axis 36 of the guide hole 34. The dental drill bit 10 is then inserted through the guide hole 34, and the hole 34 is drilled using the dental drill bit 10 being guided by the guide hole 34, or by a guide sleeve (not shown) provided in the guide hole 34. Because of the side cutting capability of the spherical drill head 16, the drill bit 10 will properly engage the oblique bone surface 30 and not "slide" sideways on the oblique bone surface 30. The latter could otherwise cause the surgical template 32 to be dislocated, which in turn could result in that the hole is not properly drilled (it could for instance have an angle deviating from the planned angle). Bone rests resulting from the drilling may be transported away by means of the helical flute(s) 26.
1. A dental drill bit (10) in combination with a surgical template (32) provided with
a guide hole (34) adapted to guide the dental drill bit directly or via a guide sleeve
provided in the guide hole, the dental drill bit comprising a first end (12), a second
end (14), a spherical drill head (16) arranged at the first end, and at least one
helical flute (26) extending from the spherical drill head towards the second end,
wherein the portion (24) of the dental drill bit having the at least one helical flute
is cylindrical for guiding the dental drill bit (10) by the guide hole (34) directly
or via a guide sleeve provided in the guide hole (34), wherein the maximum diameter
(D1) of the spherical drill tip is equal or substantially equal to the diameter (D2)
of the portion (24) of the dental drill bit having the at least one helical flute,
the drill bit (10) further comprising a longitudinal axis (20) extending through the
first end and the second end, wherein the longitudinal axis lies in a plane in which
the spherical drill head defines a circle sector having a sector angle (θ) greater
than 180 deg.
2. A dental drill bit according to claim 1, wherein the spherical drill head comprises
a plurality of cutting edges (18).
3. A dental drill bit according to any preceding claim, wherein the spherical drill head
is radially centralized.
4. A dental drill bit according to any preceding claim, wherein a portion (22) of the
dental drill bit at the second end is adapted for attachment to a drilling machine.
5. A dental drill bit according to any preceding claim, wherein the at least one helical
flute has a pitch in the range of 3-20 deg.
6. A dental drill bit according to any preceding claim, wherein the at least one helical
flute consists of two entwined helical flutes (26a, 26b).
1. Zahnärztlicher Bohrer (10) in Kombination mit einer chirurgischen Schablone (32),
die mit einem Führungsloch (34) bereitgestellt ist, das dazu ausgelegt ist, den zahnärztlichen
Bohrer direkt oder über eine in dem Führungsloch bereitgestellte Führungsbuchse zu
führen, wobei der zahnärztliche Bohrer ein erstes Ende (12), ein zweites Ende (14),
einen am ersten Ende angeordneten kugelförmigen Bohrkopf (16) und mindestens eine
schraubenförmige Nut (26), die sich vom kugelförmigen Bohrkopf in Richtung des zweiten
Endes erstreckt, umfasst, wobei der Abschnitt (24) des zahnärztlichen Bohrers, der
die mindestens eine schraubenförmige Nut aufweist, zylindrisch ist, um den zahnärztlichen
Bohrer (10) durch das Führungsloch (34) direkt oder über eine im Führungsloch (34)
bereitgestellte Führungsbuchse zu führen, wobei der maximale Durchmesser (D1) der
kugelförmigen Bohrspitze dem Durchmesser (D2) des Abschnitts (24) des zahnärztlichen
Bohrers, der die mindestens eine schraubenförmige Nut aufweist, entspricht oder im
Wesentlichen entspricht, wobei der Bohrer (10) ferner eine Längsachse (20) umfasst,
die sich durch das erste Ende und das zweite Ende erstreckt, wobei die Längsachse
in einer Ebene liegt, in welcher der kugelförmige Bohrkopf einen Kreissektor definiert,
der einen Sektorwinkel (θ) von mehr als 180 Grad aufweist.
2. Zahnärztlicher Bohrer nach Anspruch 1, wobei der kugelförmige Bohrkopf eine Vielzahl
von Schneidkanten (18) umfasst.
3. Zahnärztlicher Bohrer nach einem der vorhergehenden Ansprüche, wobei der kugelförmige
Bohrkopf radial zentriert ist.
4. Zahnärztlicher Bohrer nach einem der vorhergehenden Ansprüche, wobei ein Abschnitt
(22) des zahnärztlichen Bohrers am zweiten Ende dazu ausgelegt ist, an einer Bohrmaschine
befestigt zu werden.
5. Zahnärztlicher Bohrer nach einem der vorhergehenden Ansprüche, wobei die mindestens
eine schraubenförmige Nut einen Neigungswinkel im Bereich von 3-20 Grad aufweist.
6. Zahnärztlicher Bohrer nach einem der vorhergehenden Ansprüche, wobei die mindestens
eine schraubenförmige Nut aus zwei verschlungenen schraubenförmigen Nuten (26a, 26b)
besteht.
1. Foret dentaire (10) combiné à un gabarit chirurgical (32) doté d'un trou de guidage
(34) adapté pour guider le foret dentaire directement ou via un manchon de guidage
aménagé dans le trou de guidage, le foret dentaire comprenant une première extrémité
(12), une deuxième extrémité (14), une tête de foret sphérique (16) disposée sur la
première extrémité, et au moins une goujure hélicoïdale (26) s'étendant depuis la
tête de foret sphérique vers la deuxième extrémité, dans lequel la portion (24) du
foret dentaire ayant l'au moins une goujure hélicoïdale est cylindrique pour le guidage
du foret dentaire (10) par le trou de guidage (34) directement ou via un manchon de
guidage aménagé dans le trou de guidage (34), dans lequel le diamètre maximal (D1)
du foret sphérique est égal ou sensiblement égal au diamètre (D2) de la portion (24)
du foret dentaire ayant l'au moins une goujure hélicoïdale, le foret (10) comprenant
en outre un axe longitudinal (20) s'étendant au travers de la première extrémité et
de la deuxième extrémité, dans lequel l'axe longitudinal se trouve dans un plan dans
lequel la tête de foret sphérique définit un secteur circulaire ayant un angle de
secteur (θ) supérieur à 180 degrés.
2. Foret dentaire selon la revendication 1, dans lequel la tête de foret sphérique comprend
une pluralité d'arêtes coupantes (18) .
3. Foret dentaire selon une quelconque revendication précédente, dans lequel la tête
de foret sphérique est radialement centralisée.
4. Foret dentaire selon une quelconque revendication précédente, dans lequel une portion
(22) du foret dentaire au niveau de la deuxième extrémité est adaptée pour une fixation
à une machine de forage.
5. Foret dentaire selon une quelconque revendication précédente, dans lequel l'au moins
une goujure hélicoïdale a un pas dans la plage de 3 à 20 degrés.
6. Foret dentaire selon une quelconque revendication précédente, dans lequel l'au moins
une goujure hélicoïdale consiste en deux goujures hélicoïdales entrelacées (26a, 26b).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description